Influence of oxygen in architecting large scale nonpolar GaN nanowires

Abstract

Manipulation of surface architecture of semiconducting nanowires with a control in surface polarity is one of the important objectives for nanowire based electronic and optoelectronic devices for commercialization. We report the growth of exceptionally high structural and optical quality nonpolar GaN nanowires with controlled and uniform surface morphology and size distribution, for large scale production. The role of O contamination (~1-10^5 ppm) in the surface architecture of these nanowires is investigated with the possible mechanism involved. Nonpolar GaN nanowires grown in O rich condition show the inhomogeneous surface morphologies and sizes (50 - 150 nm) while nanowires are having precise sizes of 40(5) nm and uniform surface morphology, for the samples grown in O reduced condition. Relative O contents are estimated using electron energy loss spectroscopy studies. Size-selective growth of uniform nanowires is also demonstrated, in the O reduced condition, using different catalyst sizes. Photoluminescence studies along with the observation of single-mode waveguide formation, as far field bright violet multiple emission spots, reveal the high optical quality of the nonpolar GaN nanowires grown in the O reduced condition.Comment: 27 Pages, 8 figure, journa

Optical properties of AlGaN nanowires synthesized via ion beam techniques

“…The as-grown GaN NWs show a peak centered at ~3.28 eV, which is attributed to the recombination of the neutral donor-acceptor pair (DAP), originating due to a transition of electrons from the possible presence of a shallow donor state of nitrogen vacancy (VN) to a deep acceptor state of Ga vacancy (VGa). 22,23 The quenching of PL emission in the irradiated sample ( Fig. 5) is attributed to the trapping of radiative charge carriers by large number of point defects produced by the high energy ion irradiation.…”

Localized tip enhanced Raman spectroscopic study of impurity incorporated single GaN nanowire in the sub-diffraction limit

“…Detailed growth process was reported elsewhere. 17 Mg doped nonpolar GaN nanowires were synthesized using Mg 3 N 2 (Alfa Aesar) as a source for incorporating Mg and was reported earlier. 18 Au nanoparticles of size ~55(+10) nm on Si substrate were used to grow the Mg doped GaN nanowires.…”

Native defect-assisted enhanced response to CH4 near room temperature by Al0.07Ga0.93N nanowires

“…The peak at ~3.28 eV is attributed to the recombination of the donor-acceptor pair (DAP) for a transition of electrons from a shallow donor state (V N , O N ) to a deep acceptor state of V Ga . 24,41 The phonon replica of DAP transition is also observed in the PL spectra. In case of the GaN sample irradiated and post-annealed at 1000 °C, the PL spectrum ( Fig.…”